In the last couple of months Steve Bliss has lead the work on defining an extension of the LDraw file format. The extension, called BFC, will allow LEGO CAD programs based on the LDraw parts library to render LDraw'ings almost twice as fast as now. Great care has been taken to make sure that LDraw, and older LDraw compatible programs, also will be able to render files using the BFC extension correctly, albeit without the speed increase.

The BFC extension adds the possibility of using back-face culling when rendering LDraw'ings. This means that the programs can check which surfaces have the visible side turned away from the viewer, and skip drawing them.